Sea lettuce furrowing trials – day 2

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Our roving reporter had a look at the furrows just after lunch when the furrows were beginning to be exposed after a second high tide since the initial ploughing was carried out, and then again at low tide. Our thoughts are thus:

At the top of the furrows (nearest the road), the furrows are flattening, but still visible. Further down, the furrows are maintaining integrity (shape, etc) and water is flowing along them; this is good news.

The furrows started too far up the beach – we hope this won’t negatively affect the conclusions being reached.

The furrows have been made in an area which is different to where the trial should take place: different particle sizes, packing, anoxic depths and areas, etc.

While this initial ploughing was done in that area to ‘test the integrity of the furrows’ (ie, could they be done, would they last, would they help drainage, etc), we have to ask if they will go on to do a proper trial, or has this has just been set up to fail? We sincerely hope the former, and that we will get enough potentially positive results for a full and timely trial to be held next year.

Why do we want furrows?

Based on other trials, effective furrowing could:

Drain the beach’s standing water so that sea lettuce sporelings would not get a hold, and thus cut down on the amount growing;

Wash nutrient-laden water further out into the gyre (currents), which flows past Havre des pas to the east; these nutrients would be picked up by oysters;

Create drier banks for valuable sea grass to take a hold (they prefer these conditions);

Take the anoxic layer (the smelly grey bit without enough oxygen) down further, enabling seagrass to get a better hold.

Furrowing could be used until we have the nitrates-into-the-water problem solved. We cannot control the sea temperature of heat and sunshine hours, and we’ve lost control over the current (when La Collette was built), but we can do our best to control other factors.

What next?

We would say that this approach is a new arena for the States and we can appreciate them wanting to tread (plough) carefully. We hope, however, they will start pulling in, and listening to, even more expert advice, so we (Jersey) can make a good inroads into solving the problem.

First few pics from the afternoon; scroll down for further pics taken at low tide:

Sea lettuce furrowing trials in St Aubin’s Bay – day 2, second tide since furrowing on way out – 31 May 2017Sea lettuce furrowing trials in St Aubin’s Bay – day 2, second tide since furrowing on way out – 31 May 2017Sea lettuce furrowing trials in St Aubin’s Bay – day 2, second tide since furrowing on way out – 31 May 2017Furrows after two high tides – early evening, 31 May 2017Furrows after two high tides – early evening, 31 May 2017Furrows after two high tides – early evening, 31 May 2017Furrows after two high tides – early evening, 31 May 2017Furrows after two high tides – early evening, 31 May 2017